IMOs can be made in several ways, but they are primarily derived from a sugar called maltose. IMO is promoted as a prebiotic fiber with a light sweetness profile. Its functional properties (i.e., moisture retention, low viscosity) make it well-suited for nutrition bars, cookies, candies, and the like. In order to fully understand IMOs and how the body processes them, we first need to understand how starches are digested in the body. Starches, also known as polysaccharides, are long and sometimes branched chains of glucose molecules. Initially, starch digestion begins in the small intestine with an enzyme called α-amylase. A-amylase breaks these long glucose chains into much shorter chains, called oligosaccharides, which are composed of anywhere from two to approximately 10 glucose units. Following this, specific enzymes on the brush border of the small intestine break down these oligosaccharides even further, into individual glucose units (monosaccharides) which are then absorbed.
Psyllium husk is a type of fiber commonly used as a gentle, bulk-forming laxative. With no net carbs and a whopping 7 grams of fiber per two tablespoon serving, ground psyllium is an easy way to increase fiber intake on the keto diet. “It works great as a binding agent in recipes,” Yule says. “Just make sure to consume it with plenty of water, coconut water, or juice to avoid dehydration.” Add a tablespoon to your beverage, and you’re good to go.
The increased awareness regarding the importance of fiber, in addition to its distinct metabolic effects, has resulted in a surge of companies switching to an alternative fiber known as soluble corn fiber (SCF). Interestingly, SCF has been available on the US market since 2007 and is used in foods and beverages across the Americas, Europe, and Southeast Asia. SCF is produced through an extensive process: corn syrup is exposed to a suite of enzymes for at least 48 hours, some of which are found in the brush border of your small intestine, as well as the pancreas.[5] Notably, a large majority of the corn syrup contains easily digestible carbohydrates; however, a small portion is, in fact, not digestible. At the end of this enzymatic exposure, a stream of digestion-resistant carbohydrates remains and is subsequently filtered several times. The resulting product is a “true fiber” that contains a mixture of α-1,6, α-1,4, α-1,2, and α-1,3 glucosidic linkages, which, as mentioned above, contribute to its low digestibility.
The increased awareness regarding the importance of fiber, in addition to its distinct metabolic effects, has resulted in a surge of companies switching to an alternative fiber known as soluble corn fiber (SCF). Interestingly, SCF has been available on the US market since 2007 and is used in foods and beverages across the Americas, Europe, and Southeast Asia. SCF is produced through an extensive process: corn syrup is exposed to a suite of enzymes for at least 48 hours, some of which are found in the brush border of your small intestine, as well as the pancreas.[5] Notably, a large majority of the corn syrup contains easily digestible carbohydrates; however, a small portion is, in fact, not digestible. At the end of this enzymatic exposure, a stream of digestion-resistant carbohydrates remains and is subsequently filtered several times. The resulting product is a “true fiber” that contains a mixture of α-1,6, α-1,4, α-1,2, and α-1,3 glucosidic linkages, which, as mentioned above, contribute to its low digestibility.
Seeds are another high-fiber food that you can eat on keto, but only occasionally to stay in ketosis. Full seeds, ground seeds and seed butters will help to increase your fiber intake and minimize keto flu symptoms like constipation. Plus, they supply important nutrients, including essential fatty acids and protein, and are known to support cardiovascular health.
In most cases, if you grab a low-carb snack at random from the grocery store shelf and look at the label, a common nutrient profile contains around 20 grams of carbohydrates, yet maybe 15 of those grams are from “fiber.” The result is five grams of net carbs, right? Not so fast. . . if a Type I diabetic were to consume that bar, cookie, or brownie with the five grams of net carbs, there should not be a need for insulin since, theoretically, there is minimal glucose (blood sugar) entering the system from those five net carbs, which shouldn’t require an insulin response. Unfortunately, theory and outcome do not always match.
Lastly, one of the advertised benefits of IMO is possible prebiotic activity. Prebiotics are critical, as they feed the beneficial bacteria in our digestive system, specifically in the large intestine. These bacteria have several amazing functions, such as lowering body fat, improving insulin sensitivity, and lowering depression. Two “gold standard” prebiotics in the industry are inulin and fructooligosaccharides (FOS). Inulin and FOS are non-digestible carbohydrates that robustly increase beneficial bacteria. The challenge, however, is that both inulin and FOS, due to their rapid digestibility by intestinal bacteria, result in low gastric tolerance, and, ultimately, gastric distress. Additionally, inulin and FOS, when added to protein bars or other goods, may degrade over time into individual sugar units. Regardless, one study comparing inulin to IMOs, found that the prebiotic activity in inulin is 14 times greater than that of IMOs.[4] This is logical because, as you recall from above, approximately 70% to 90% of IMOs are digested. As such, only a small portion of these prebiotic fibers make it to the large intestine, in which two out of three studies have demonstrated that this small portion may indeed have some prebiotic effects.
One of the first studies to examine IMO syrups[2] had six subjects consume 25 grams of IMO syrup. These researchers found that glucose levels increased from 109 mg/dL pre-ingestion to a peak of 136 mg/dL 30 min post-ingestion. Additionally, insulin rose to nearly parallel levels with that of glucose from 4.8 μU/mL pre-ingestion to nearly 32 μU/mL at 30 min post-ingestion. These values clearly indicate that some digestion is occurring. Furthermore, these researchers found that IMO was about 83% as digestible as maltose under resting conditions and about 69% as digestible after the exercise period. Taken together, this suggests that a large majority of the carbohydrate in the IMO syrup was, in fact, digested, absorbed, and metabolized.

Lastly, one of the advertised benefits of IMO is possible prebiotic activity. Prebiotics are critical, as they feed the beneficial bacteria in our digestive system, specifically in the large intestine. These bacteria have several amazing functions, such as lowering body fat, improving insulin sensitivity, and lowering depression. Two “gold standard” prebiotics in the industry are inulin and fructooligosaccharides (FOS). Inulin and FOS are non-digestible carbohydrates that robustly increase beneficial bacteria. The challenge, however, is that both inulin and FOS, due to their rapid digestibility by intestinal bacteria, result in low gastric tolerance, and, ultimately, gastric distress. Additionally, inulin and FOS, when added to protein bars or other goods, may degrade over time into individual sugar units. Regardless, one study comparing inulin to IMOs, found that the prebiotic activity in inulin is 14 times greater than that of IMOs.[4] This is logical because, as you recall from above, approximately 70% to 90% of IMOs are digested. As such, only a small portion of these prebiotic fibers make it to the large intestine, in which two out of three studies have demonstrated that this small portion may indeed have some prebiotic effects.


But do you need that much fiber to stay healthy? Perhaps not. Several different large reviews of dozens of studies have found that eating more fiber than the average person can reduce your risk of dying from both heart disease and cancer by at least 10%[*][*][*]. The benefits of eating fiber in these studies occurred with a total daily fiber intake between 18-26 grams, much lower than the USDA and NAS recommendations.
IMOs can be made in several ways, but they are primarily derived from a sugar called maltose. IMO is promoted as a prebiotic fiber with a light sweetness profile. Its functional properties (i.e., moisture retention, low viscosity) make it well-suited for nutrition bars, cookies, candies, and the like. In order to fully understand IMOs and how the body processes them, we first need to understand how starches are digested in the body. Starches, also known as polysaccharides, are long and sometimes branched chains of glucose molecules. Initially, starch digestion begins in the small intestine with an enzyme called α-amylase. A-amylase breaks these long glucose chains into much shorter chains, called oligosaccharides, which are composed of anywhere from two to approximately 10 glucose units. Following this, specific enzymes on the brush border of the small intestine break down these oligosaccharides even further, into individual glucose units (monosaccharides) which are then absorbed.
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